Dynamic service information for the access network

ABSTRACT

A method and an apparatus for providing an access network element in a communication network system with information are disclosed, the information enabling the access network element to perform service based processing on data belonging to an application session.

FIELD OF THE INVENTION

The present invention relates to communication networks, and inparticular to a service based control of access bearers and serviceflows (hereinafter also referred to as sessions) and an access networkenforcing a result of the service based control.

BACKGROUND OF THE INVENTION

In 3GPP (Third Generation Partnership Project) network systems servicebased control such as charging control and QoS (Quality of Service)control is becoming standardized. For service based charging control, aCharging Rules Function (CRF) is introduced to the 3GPP referencearchitecture. For service based QoS control, a Policy Decision Function(PDF) is introduced to the 3GPP reference architecture.

Both the CRF and PDF interface with an Application Function (AF) to getapplication session and media component information to be used for rulecreation, i.e. the CRF uses the application session and media componentinformation for charging rule creation, and the PDF uses the applicationsession and media component information for QoS rule creation. The AFsends information about the application session and media component(s)both to the CRF and PDF including e.g. information on a filter of amedia component and a service in question (e.g. Application Id and/orMedia Type).

Both the CRF and PDF interface with a Gateway (GW) to give rules to theGW which enforces the rules.

One key principle for enhancing the performance of a core network is tomaximize the usage of service management and to minimize the usage ofservice control signaling. This means that as much as possibleinformation is pre-configured in network elements and service controlsignaling is used only when absolutely necessary.

Rules (e.g. charging or QoS rules) pre-configured in the GW are used ifpossible, because this way, it is possible to decrease the amount ofservice control signaling traffic.

If the filter of an application session component is dynamic, the GWgets the filter from the AF through a service based control entity suchas the CRF and PDF. With the filter, the GW can identify a service flow.

However, the GW is not able to apply pre-configured service specificrules in case of receiving dynamic information from the AF through theservice based control entity.

SUMMARY OF THE INVENTION

It is an object of the present invention to enhance the usage of servicemanagement in a communication network.

According to the invention, this object is solved by a method and anapparatus for providing an access network element in a communicationnetwork system with information enabling the access network element toperform service based processing on data belonging to an applicationsession.

Information on a service in question (e.g. an Application Id and/or aMedia Type) is sent from a service based control entity such as a CRF orPDF to an access network, e.g. a Gateway (GW). The CRF and the PDF mayget the information on the service in question from an ApplicationFunction (AF). This information may be provided by the AF for a mediacomponent or for the whole application session. In the latter case, itis assumed that if there are multiple media components within anapplication session, those are of the same service. The service basedcontrol entity may then provide this information to the GW for a serviceflow or for the whole access bearer (e.g. PDP context or WLAN tunnel).In the latter case, it is assumed that if there are multiple serviceflows within an access bearer, those are of the same service.

According to the invention, the GW is allowed to apply pre-configuredservice specific rules also in case of receiving dynamic informationfrom the AF through the CRF and PDF.

Moreover, the service information may also be used in the GW when/ifcorrelating information received from the CRF and PDF. If the GWreceives information via two routes, the GW may want to check that thereis no conflict in the information or may want to correlate thatinformation for the implementation. The information received from theCRF may contain e.g. a filter, a charging rule instruction and serviceinformation. The information received from the PDF may contain e.g. afilter, a QoS rule instruction and service information. With the serviceinformation, the GW is enabled to correlate information received fromthe CRF and the PDF and to check that there is no conflict in thefilters. If there is no conflict in the information received from theCRF and the PDF, the GW can optimize the storage of the information bystoring the service information and the filter only once.

In the following, the invention will be described by way of preferredembodiments thereof taking into account the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic block diagram illustrating a 3GPP referencearchitecture to which the invention is applicable.

FIG. 2 shows a schematic block diagram illustrating an access networkelement and a network control element according to an embodiment of theinvention.

FIG. 3 shows flow charts illustrating procedures of a control method anda processing method according to the embodiment of the invention.

FIG. 4 shows a signaling diagram illustrating initial authorization andpolicy at an access bearer establishment with AF involved according toan implementation example of the invention.

FIG. 5 shows a signaling diagram illustrating initial policy for aservice flow with AF involved according to the implementation example ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an architecture of a network system to which the inventionis applicable. The network system comprises an access network includinga gateway 10 such as a GGSN (Gateway GPRS Support Node) connected to aGPRS (General Packet Radio Services) access network, i.e. to an SGSN(Serving GPRS Support Node), via a Gn/Gp interface or a PDG (Packet DataGateway) connected to a WLAN access network, i.e. to a WAG (WLAN AccessGateway), via a Wp interface. According to CDMA (Code Division MultipleAccess), the gateway 10 is formed by a PDSN (Packet Data Serving Node).In FIG. 1, a TPF (Traffic Plane Function) is co-located with theGGSN/PDG for flow based charging. The network system further comprisesservice based control entities such as a CRF connected to the gateway 10via a Gx interface, a PDF connected to the gateway 10 via a Go interfaceand a Credit Control block 11 connected to the gateway 10 via a Gyinterface. An application function AF is connected to the CRF via a Rxinterface, and to the PDF via a Gq interface. The Application Function(AF) is an element of the network system, which supports applicationsession and media component based control of IP bearer resources whenrequired. An IMS (IP Multimedia Subsystem) of the network system, whichcomprises a P-CSCF (Proxy Call Session Control Function) enables supportfor IP multimedia applications. The P-CSCF of the IMS may act as an AF.As shown in FIG. 1, the P-CSCF is connected to the Credit Control block11 via an Ro interface, to the CRF via the Rx interface and to the PDFvia the Gq interface.

FIG. 2 illustrates an access network element 100 such as a gateway 10shown in FIG. 1 and a network control element 200 such as a CRF or PDFshown in FIG. 1 according to an embodiment of the invention. FIG. 3illustrates a service based control method and a service basedprocessing method according to the embodiment of the invention. Thesemethods may also be implemented as computer program products which mayrun on processors of the network control element 200 or the accessnetwork element 100. Moreover, it is to be noted that the blocks shownin FIG. 2 are for illustrating the concept of the invention and it is tobe understood that the access network element 100 and the networkcontrol element 200 may have further means e.g. for acting as gatewayand service based control entity, respectively. In addition, functionsof different blocks shown in FIG. 2 may be combined to be performed inone block or functions of one block may be further separated intosub-blocks.

The network control element 200 is an element for performing servicebased control in a communication network system such as the system shownin FIG. 1. As shown in FIG. 2, the network control element 200 comprisesa first receiving block 201, a deciding block 202, a generating block203 and a first sending block 204. When a message from a supportingnetwork entity 300 supporting an application session (e.g. from anApplication Function or P-CSCF) is received by the first receiving block201 (step S41 in FIG. 3), the deciding block 202 decides controlinformation on the basis of the received message which comprisesapplication session and/or media component information (step S42 in FIG.3). The control information are decided for service flows/access bearersassociated with the application session. The generating block 203generates a decision message such that the decision message comprisesthe decided control information and information on a service in question(step S43 in FIG. 3), the decision message enabling the access networkelement 100 to perform service based processing on data belonging to theapplication session. The generating block 203 may generate the decisionmessage such that the decision message further comprises an indicationwhether the information on the service in question is valid for thewhole access bearer associated with the application session. Finally,the first sending block 204 sends the decision message to the accessnetwork element 100 (step S44 in FIG. 3). This may happen either whenrequested by the access network element 100 or without a request fromthe access network element 100.

The access network element 100 is an element for processing and routingdata belonging to an application session to a packet data network of thecommunication network system. As shown in FIG. 2, the access networkelement 100 comprises a second receiving block 101, a detecting block102, an identifying block 103 and a processing block 104. When thesecond receiving block 101 receives a decision message from the networkcontrol element 200 (step S31 in FIG. 3), the detecting block 102detects decided control information and information on a service inquestion from the decision message (step S32 in FIG. 3). The identifyingblock 103 identifies a service in question by using the information on aservice in question (step S33 in FIG. 3). Thus, the processing block 104is enabled to process data belonging to an application session inaccordance with the identified service in question and the detecteddecided control information (step S34 in FIG. 3).

The control information may be stored in the access network element 100in a storage unit (not shown). In this case, the processing block 104 ofthe access network element 100 can use the information on a service inquestion to access the control information and to select controlinformation for the service. This may happen e.g. if sufficient controlinformation is not received from the network control element 200.

The access network element 100 may further comprise a second sendingblock 105 which may send a request message to the network controlelement 200, requesting a decision message from the network controlelement 200. This request message may be sent in response to the receiptof a request for establishing or modifying an access bearer by thesecond receiving block 101. Alternatively or in addition, the requestmessage may be sent in case the identifying block 103 identifies databelonging to a service flow. Moreover, a signaling message may be sentto a user equipment (not shown) after the detecting block 102 hasdetected decided control information and information on a service inquestion from the decision message.

The first receiving block 201 may receive updated application sessionand/or media components information. Thereupon, the deciding block 202decides updated control information. In response thereto, the generatingblock 203 may generate an updated decision message and the first sendingblock 204 sends the updated decision message to the access networkelement 100. This may happen either when requested by the access networkelement 100 or without a request from the access network element 100.

For service based charging control, as network control element 200 theCharging Rules Function CRF may be introduced to the network system. Forservice based QoS control, as network control element 200 the PolicyDecision Function PDF may be introduced to the network system.

Both the CRF and PDF interface with the Application Function (AF) to getapplication session and/or media component information to be used forrule creation (CRF for charging rule creation and PDF for QoS rulecreation). The AF sends information about the application session and/ormedia component(s) both to the CRF and PDF including e.g. information onthe filter of a media component and the service in question (e.g.Application Id or Media Type). Both the CRF and PDF interface with thegateway (GW) 10 acting as the access network element 100 to give rulesto the GW 10.

According to the invention, information on the service in question (e.g.the Application Id) is sent from the service based control entities,i.e. the CRF and PDF, to the gateway 10 of the access network. The CRFand the PDF get this information from the AF. This information may besent for each media component or for the whole application session. Inthe latter case, it is assumed that if there are multiple mediacomponents within an application session, those are of the same service.The CRF and the PDF may then provide this information to the GW for aservice flow or for the whole access bearer (e.g. PDP context or WLANtunnel). In the latter case, it is assumed that if there are multipleservice flows within an access bearer, those are of the same service. Asdescribed above, the information may be sent by the service basedcontrol entities upon a request from the gateway 10 or independentlythereof, e.g. if there are changes in application session and/or mediacomponent information.

FIGS. 4 and 5 show a provision of information on a service in questionto a Gateway (GW) according to an implementation example of theinvention. In FIGS. 4 and 5, communications with a PDF are illustrated,but similar communications may take place with a CRF or any servicebased control entity. As described above, the PDF and CRF are allowed tosend decision messages to the GW without a request from the GW, e.g. ifthere are changes in application session and/or media componentinformation.

FIG. 4 shows a signaling diagram illustrating an initial authorizationand policy at an access bearer establishment.

When receiving a request for an access bearer establishment (e.g. inGPRS, a Create PDP (Packet Data Protocol) Context Request), the Gatewayinitiates an authorization and policy request to the PDF.

In communication 1 in FIG. 4, an Application Function (AF) sends aSession Authorization Indication (Application/Service Information,Authorization Token Request) message to the PDF. This message may betriggered by an application session establishment event in the AF (e.g.the AF receiving an AF session signaling message containing sessiondescription information (e.g. SDP)). The Application/Service Informationincludes for each media component an application id, packet filterinformation, direction information, QoS information and applicationspecific information. The Authorization Token Request is included if theAF wants the PDF to allocate an authorization token.

The AF may send information on multiple application sessions to the PDF.It is also possible that multiple AFs send information on theapplication sessions to the PDF.

Upon receiving the message from the AF, the PDF allocates anauthorization token if requested by the AF and replies by sending aSession Authorization Acknowledgment (Authorization Token) message tothe AF (communication 2 of FIG. 4). The Authorization Token then is sentfrom the AF to a User Equipment (UE) initiating the sessionestablishment (e.g. in case of IMS (Internet Protocol MultimediaSubsystem) and PSS (Packet Switched Streaming Service).

In communication 3 of FIG. 4, the Gateway receives a request for anaccess bearer establishment, i.e. an AP Request(Authorization Token,Flow Ids) message. The AP Request is a request to a specific accesspoint of the GW. The Authorization Token and Flow Ids are available ifsent by the UE with the AP Request message. Multiple sets ofAuthorization Token+Flow Ids may also be available.

Upon receiving the AP Request message, the Gateway resolves a PDFaddress by using the Authorization Token or by using PDF addressinformation stored in the Gateway. The Gateway sends a Request(Authorization Token, Flow Ids) message to the PDF (communication 4 inFIG. 4). The Authorization Token+Flow Ids are included if received incommunication 3. Multiple sets of Authorization Token+Flow Ids may alsobe included.

Upon receiving the request from the Gateway, the PDF uses theAuthorization Token and Flow Ids to access the information sent by theAF in communication 1. The PDF performs an authorization and policydecision and sends a Decision (Access Bearer QoS Rule, Access BearerApplication Id, Service Flow Filter, Service Flow QoS Rule, Service FlowApplication Id) message to the Gateway (communication 5 of FIG. 4). TheAccess Bearer QoS Rule indicates max values for a QoS class and bitrates of the access bearer. The Access Bearer Application Id may beincluded if all the service flows within the access bearer are of thesame service. For each service flow, the Service Flow Filter is used inthe GW to identify the service flow. For each service flow, the ServiceFlow QoS Rule indicates max values for the QoS class and bitrates of theservice flow. For each service flow, the Service Flow Application Idindicates the service in question.

Upon receiving the Decision message, the Gateway enforces theauthorization and policy decision. Finally, in communication 6 of FIG.4, the Gateway acknowledges the access bearer establishment.

The signaling diagram of FIG. 4 may also be applied to access bearermodification.

FIG. 5 shows a signaling diagram illustrating an initial policy for aservice flow. In case of IP multimedia services over GPRS (GeneralPacket Radio System) it is possible to know beforehand which serviceflows will be carried on the access bearer, because 3GPP has specifiedthat a UE has to indicate the service flows to the Gateway at an accessbearer establishment/modification by sending the Authorization Token andFlow Ids. However, this does not apply to all access networks and to allapplication sessions. In some access networks, it may not be possible tosend the Authorization Token and Flow Ids from the UE to the Gateway atthe access bearer establishment/modification. And in case of legacyelements, AFs or UEs, the legacy elements may not support the usage ofthe Authorization Token and Flow Ids as binding information. For examplein these cases, the Gateway initiates an initial policy request whenidentifying a service flow.

In communication 1 of FIG. 5 an AF sends a Session AuthorizationIndication (Application/Service Information, Authorization TokenRequest) message to a PDF. This message may be triggered by anapplication session establishment event in the AF. TheApplication/Service Information includes for each media component anapplication id, packet filter information, direction information, QoSinformation and application specific information. The AuthorizationToken Request is included if the AF wants the PDF to allocate anauthorization token. The AF may send information on multiple applicationsessions to the PDF. However, it is also possible that multiple AFs sendinformation on the application sessions to the PDF.

Upon receiving the message, the PDF allocates an authorization token ifrequested by the AF and replies by sending a Session AuthorizationAcknowledgment (Authorization Token) message to the AF (communication 2of FIG. 5). After receiving the acknowledgment message, the AF mayforward the Authorization Token to a UE initiating the sessionestablishment (at least in case of IMS and PSS).

In block 3 of FIG. 5 a Gateway identifies a service flow for which PDFcontrol is required. The Gateway resolves a PDF address by using PDFaddress information stored in the Gateway. The Gateway sends a Request(Service Flow Filter) message to the PDF (communication 4 of FIG. 5).The Service Flow Filter is derived from a received packet of theidentified service flow.

Upon receiving the Request message from the Gateway, the PDF uses theService Flow Classifier to access the information sent by the AF incommunication 1. The PDF performs a policy decision and sends a Decision(Access Bearer QoS Rule, Access Bearer Application Id, Service FlowFilter, Service Flow QoS Rule, Service Flow Application Id) message tothe Gateway (communication 5 of FIG. 5). The Access Bearer QoS Rule isincluded if there is a need to change the previous QoS rule of theaccess bearer. The Access Bearer Application Id may be included if allthe service flows within the access bearer are of the same service. TheService Flow Filter is used in the GW to identify the service flow. TheService Flow QoS Rule indicates max values for the QoS class andbitrates of the service flow. The Service Flow Application Id indicatesthe service in question.

Finally, after receiving the Decision message from the PDF, the Gatewayenforces the policy decision.

In the foregoing, a method and an apparatus for providing an accessnetwork element in a communication network system with information aredisclosed, the information enabling the access network element toperform service based processing on data belonging to an applicationsession.

It is to be understood that the above description is illustrative of theinvention and is not to be construed as limiting the invention. Variousmodifications and applications may occur to those skilled in the artwithout departing from the true spirit and scope of the invention asdefined by the appended claims.

1. A network control element for performing service based control in acommunication network system, the network control element comprising:receiving means for receiving a message from a supporting network entitysupporting an application session, the message comprising at least oneof application session and media component information; deciding meansfor deciding control information based on the message; generating meansfor generating a decision message such that the decision messagecomprises the control information and information on a service inquestion, the decision message enabling an access network element toperform service based processing on data belonging to the applicationsession; and sending means for sending the decision message to theaccess network element.
 2. The network control element according toclaim 1, wherein the receiving means is configured to receive a requestmessage from the access network element requesting the decision messagefrom the network control element, and the generating means is configuredto generate the decision message and the sending means is configured tosend the decision message to the access network element in response tothe request message received by the receiving means.
 3. The networkcontrol element according to claim 1, wherein the generating means isconfigured to generate the decision message and the sending means isconfigured to send the decision message to the access network elementwithout any request from the access network element.
 4. The networkcontrol element according to claim 1, wherein the receiving means isconfigured to receive at least one of updated application session andmedia component information, the deciding means is configured to decideupdated control information based on at least one of the updatedapplication session and media component information, and the generatingmeans is configured to generate an updated decision message and thesending means is configured to send the updated decision message.
 5. Thenetwork control element according to claim 1, wherein the generatingmeans is configured to generate the decision message such that thedecision message further comprises an indication of whether theinformation on the service in question is valid for a whole accessbearer associated with the application session.
 6. The network controlelement according to claim 1, wherein the network control elementcomprises at least one of a Charging Rules Function and a PolicyDecision Function.
 7. The network control element according to claim 1,wherein the message received by the receiving means from the supportingnetwork entity comprises a Session Authorization Indication.
 8. Thenetwork control element according to claim 1, wherein the information onthe service in question comprises an Application Id.
 9. The networkcontrol element according to claim 8, wherein the information on theservice in question is valid for a service flow.
 10. The network controlelement according to claim 8, wherein the information on the service inquestion is valid for an access bearer.
 11. An access network elementfor processing and routing data belonging to an application session to apacket data network of a communication network system, the accessnetwork element comprising: receiving means for receiving a decisionmessage from a network control element; detecting means for detectingdecided control information and information on a service in questionfrom the decision message received by the receiving means; identifyingmeans for identifying the service in question by using the informationon the service in question; and processing means for processing databelonging to an application session in accordance with the service inquestion and the decided control information.
 12. The access networkelement according to claim 11, further comprising: sending means forsending a request message to the network control element, requesting adecision message from the network control element.
 13. The accessnetwork element according to claim 12, wherein the receiving means isconfigured to receive a request for establishing or modifying an accessbearer, and wherein the sending means is configured to send the requestmessage in response to receiving the request for establishing ormodifying the access bearer by the receiving means.
 14. The accessnetwork element according to claim 12, wherein the identifying means isconfigured to identify data belonging to a service flow, and the sendingmeans is configured to send the request message in response toidentification of the data belonging to the service flow by theidentifying means.
 15. The access network element according to claim 11,further comprising: storing means for storing control information,wherein the processing means is configured to use the information on theservice in question for accessing the control information stored in thestoring means and for selecting service specific control informationfrom the control information.
 16. The access network element accordingto claim 11, the access network element further comprising a gateway ofan access network.
 17. A communication network system comprising: atleast one network control element for performing service based controlin a communication network system and at least one access networkelement for processing and routing data belonging to an applicationsession to a packet data network of the communication network system,the at least one network control element comprising: first receivingmeans for receiving a message from a supporting network entitysupporting the application session, the message comprising applicationsession and media component information; deciding means for decidingcontrol information for the application session supported by thesupporting network entity, based on the message; generating means forgenerating a decision message such that the decision message comprisesthe control information and information on a service in question, thedecision message enabling the at least one access network element toperform service based processing on the data belonging to theapplication session; and first sending means for sending the decisionmessage to the at least one access network element, the at least oneaccess network element comprising: second receiving means for receivingthe decision message from the at least one network control element;detecting means for detecting the control information and theinformation on the service in question from the decision messagereceived by the second receiving means; identifying means foridentifying the service in question by using the information on theservice in question; and processing means for processing the databelonging to the application session in accordance with the service inquestion and the control information.
 18. A control method of performingservice based control in a communication network system, the methodcomprising: a receiving step of receiving a message from a supportingnetwork entity supporting an application session, the message comprisingat least one of application session and media component information; adeciding step of deciding control information based on the message; agenerating step of generating a decision message such that the decisionmessage comprises the control information and information on a servicein question, the decision message enabling an access network element toperform service based processing on data belonging to the applicationsession; and a sending step of sending the decision message to theaccess network element.
 19. A method of processing and routing databelonging to an application session, wherein the data are routed to apacket data network of a network system, the method comprising: areceiving step of receiving a decision message from a network controlelement; a detecting step of detecting decided control information andinformation on a service in question from the decision message; anidentifying step of identifying the service in question by using theinformation on the service in question; and a processing step ofprocessing data belonging to an application session in accordance withthe service in question and the decided control information.
 20. Themethod according to claim 19, wherein preconfigured control informationis stored in storing means, wherein, in the processing step, theinformation on the service in question is used for accessing thepreconfigured control information stored in the storing means and forselecting service specific control information from the stored controlinformation, in case no or insufficient control information is receivedfrom the network control element.
 21. A computer program embodied on acomputer readable medium, the computer program controlling a computer toexecute a process comprising: receiving a message from a supportingnetwork entity supporting an application session, the message comprisingat least one of application session and media component information;deciding control information based on the message; generating a decisionmessage such that the decision message comprises the control informationand information on a service in question, the decision message enablingan access network element to perform service based processing on databelonging to the application session; and sending the decision messageto the access network element.
 22. A computer program embodied on acomputer-readable medium on which the software code portions are stored,the computer program controlling a computer to execute a processcomprising: receiving a decision message from a network control element;detecting decided control information and information on a service inquestion from the decision message; identifying the service in questionby using the information on the service in question; and processing databelonging to an application session in accordance with the service inquestion and the decided control information.
 23. The computer programproduct according to claim 22, wherein the computer program product isdirectly loadable into an internal memory of the computer.
 24. A networkcontrol element for performing service based control in a communicationnetwork system, the network control element comprising: a receiverconfigured to receive a message from a supporting network entitysupporting an application session, the message comprising at least oneof application session and media component information; a firstprocessor configured to decide control information based on the message;a second processor configured to generate a decision message such thatthe decision message comprises the control information and informationon a service in question, the decision message enabling an accessnetwork element to perform service based processing on data belonging tothe application session; and a transmitter configured to send thedecision message to the access network element.
 25. An access networkelement for processing and routing data belonging to an applicationsession to a packet data network of a communication network system, theaccess network element comprising: a receiver configured to receive adecision message from a network control element; a detector configuredto detect decided control information and information on a service inquestion from the decision message received by the receiver; a firstprocessor configured to identify the service in question by using theinformation on the service in question; and a second processorconfigured to process data belonging to an application session inaccordance with the service in question and the decided controlinformation.
 26. A communication network system comprising: at least onenetwork control element for performing service based control in acommunication network system and at least one access network element forprocessing and routing data belonging to an application session to apacket data network of the communication network system, the at leastone network control element comprising: a first receiver configured toreceive a message from a supporting network entity supporting theapplication session, the message comprising application session andmedia component information; a first processor configured to decidecontrol information for the application session supported by thesupporting network entity, based on the message; a second processorconfigured to generate a decision message such that the decision messagecomprises the control information and information on a service inquestion, the decision message enabling the at least one access networkelement to perform service based processing on the data belonging to theapplication session; and a first transmitter configured to send thedecision message to the at least one access network element, the atleast one access network element comprising: a second receiverconfigured to receive the decision message from the at least one networkcontrol element; a detector configured to detect the control informationand the information on the service in question from the decision messagereceived by the second receiver; a third processor configured toidentify the service in question by using the information on the servicein question; and a fourth processor configured to process the databelonging to the application session in accordance with the service inquestion and the control information.